This is the National Stage of PCT Application No. PCT/JP00/04260 filed Jun. 28, 2000, the disclosure of which is incorporated herein by reference.
The present invention relates to an organic electroluminescence device (organic EL device) and a production method therefore. More specifically, it relates to a method for patterning an organic EL device to be formed by using a partition wall.
An organic EL device has an image display array comprising a plurality of light emitting elements comprising light emitting parts of colors, such as red, green, and blue, disposed like a matrix, with each thereof elongating in the stripe direction. In a general schematic structure thereof, first electrodes made of an ITO (indium tin oxide) are arranged parallel with each other like a plurality of stripes on a transparent substrate made of, for example, a glass. Moreover, a plurality of partition walls having an electric insulation property are formed orthogonal to the first electrodes by patterning by a predetermined distance. An organic EL medium is formed on the first electrodes without formation of the partition walls, at least by one layer. Second electrodes are formed on the organic EL medium layer along the elongation direction thereof.
The organic EL medium layer is formed while being sectioned by a deposition mask punched out in a predetermined pattern, and a partition wall. The second electrode on each organic EL medium layer is formed by deposition of a metal with a low resistivity such as an Al, a CU, an Au, and an Mg so as to prevent short circuit of adjacent ones by each partition wall.
However, the above-mentioned partition wall material, is in general, an organic substance with a relatively high water absorbing property such as a photo resist, capable of forming the cross-section in an over hanging shape, such as an inverse trapezoid. Due to the water absorbing property and the umolecular structure thereof, the photo resist tends to discharge a moisture content or an organic gas particularly in a high temperature. A problem is involved in that these deteriorate the organic EL medium, for example, form a non-light emitting part.
In view of the circumstances, an object of the present invention is to provide a method for producing an organic EL device with along life, by preventing an adverse effect to the device of the moisture content and the gas discharged from the partition wall by eliminating the partition wall, which has become unnecessary after patterning, from the substrate. Moreover, an object of the present invention is to provide an organic EL device produced by the above-mentioned method, characterized by containing substantially no partition wall.
In the present invention, as a method for eliminating apartitionwall, which has become unnecessary, from a substrate, an ashing method (dry purification) by an oxygen plasma, or an UV ozone can be used. However, as a result of the elaborate discussion for the above-mentioned objects, the present inventors have found out a further preferable method that unnecessary layers including the partition wall, which has become unnecessary, can be adhered and eliminated easily from the substrate without damaging the organic EL medium as well as the source of generating the moisture content and the organic gas, which deteriorate the organic EL medium can be eliminated by attaching adhesive sheets on the substrate after formation of the second electrode, and peeling off the adhesive sheets.
That is, the present invention relates to a method for producing an organic electroluminescence device, comprising at least a first electrode provided on a base material, an organic EL medium layer provided on the first electrode, and a second electrode provided on the organic EL medium layer, substantially not containing a partition wall, comprising the steps of providing a partition wall on a substrate, and eliminating unnecessary layers from the substrate including the partition wall, characterized in that the step of eliminating the unnecessary layers is a step of attaching the adhesive sheets having the pressure sensitive adhesive layer on the substrate after the patterning on the unnecessary layers including the partition wall so as not to contact with the organic EL medium layer between the partition walls or the second electrode, and peeling off the adhesive sheets, a production method, wherein a pressure sensitive adhesive layer provided in the adhesive sheets for adhering and eliminating the unnecessary layers is an ultraviolet ray curing type, a production method of peeling off the adhesive sheets after a curing process of the ultraviolet ray curing type pressure sensitive adhesive layer, a production method with the above-mentioned configuration, wherein the substrate and/or the unnecessary layers are preheated at the time of attaching the adhesive sheets on the substrate, and a production method with the above-mentioned configuration, wherein the substrate and/or the unnecessary layers are heated after attaching the adhesive sheets on the substrate, and peeling off the adhesive sheets while maintaining the heated state.
In the present invention, the unnecessary layers denote constituents, which become unnecessary in the production steps of the organic EL device. For example, not only a partition wall after patterning, but also an organic EL layer and an electrode may be included in some cases.